Currently, dengue is a disease of major impact on public health in Brazil. It affects half of the world's population living in endemic regions, mainly in Southeast Asia (Pacific region) and America. According to the WHO, in the one recent study it was estimated that there are about 390 million dengue infections per year (95% credible interval 284-528 million), of which 96 million (67-136 million) manifest clinically (with any severity of disease) [1]. In another study about dengue prevalence, it was estimated that 3900 million people, in 128 countries, are at risk of infection with dengue virus [2].
In Brazil, in the year 2000 the incidence was 200,000 dengue cases and in 2010 there were a million occurrences. In 2015, there were 460,502 reported cases of dengue in Brazil until March. The Southeast region had the highest number of reported cases (304,251 cases, 66.1%) compared to the country, followed by the Midwest (59,855 cases; 13%), Northeast (51,221 cases; 11.1%), North (19,402 cases; 4.2%) and South (25 773 cases, 5.6% [3].
Dengue fever (DF) and its severe form, dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS) can be caused by infection with any of the dengue serotypes DEN1, DEN2, DEN3 and DEN4.
As currently there is no antiviral drug that treats this disease and the mosquito vector (Aedes aegypti) control strategies has proven ineffective, the only way to control the advance of dengue is through prevention, with the use of a vaccine against the four types of dengue virus. At the moment, no dengue vaccines have been licensed for human use. Epidemiological studies indicate that primary infection with one dengue serotype usually causes DF, and the chance of a second infection causes DHF is 15-80 times higher than that of primary infection. Therefore, an effective dengue vaccine must be composed of the four serotypes of virus dengue [4]. However, the development of a tetravalent dengue vaccine is very difficult because this product must provide a long-term protection against all dengue virus serotypes [5].
The U.S. patent application Ser. No. 13/305,639, continuation of application Ser. No. 12/398,043, filed on Mar. 4, 2009, now U.S. Pat. No. 8,075,903, which is a continuation of application Ser. No. 10/970,640, filed on Oct. 21, 2004, now U.S. Pat. No. 7,517,531, continuation of application no. PCT/US03/13279, filed on Apr. 25, 2003, from The Government of the USA, as represented by the Secretary, department of health and human services, is entitled “Dengue tetravalent vaccine containing a common 30 nucleotide deletion in the 3′-UTR of dengue types 1, 2, 3 and 4, or antigenic chimeric dengue viruses 1, 2, 3 and 4.” The patent above refers to one product obtained from a process that include a mix of four dengue virus serotypes with a 30 nucleotide deletion or antigenic chimeric dengue virus.
The U.S. patent application Ser. No. 11/982,488, filed on Nov. 2, 2007, published on May 31, 2012 and granted on Aug. 14, 2012, from Monika Simmons et al, entitled “Induction of an immune response against dengue virus using the prime-boost approach”, describes methods for the induction of an immune response to dengue virus. The method of inducing an immune response against dengue virus comprises administration of a non-replicating immunogen followed by a boost with a tetravalent live attenuated viral vaccine. Another aspect is a method of inducing an immune response against dengue virus using a heterologous prime-boost regimen with the priming immunogen comprising a DNA expression system, an adenovirus expression vector or a Venezuelan equine encephalitis virus replicon system and the boosting immunogen comprising the same without the DNA expression system. Each expression system contains DNA sequences encoding dengue viral proteins. The patent above describes an immune scheme for dengue vaccine. In this scheme the first immunization is used a non-replicating immunogen and after a tetravalent live attenuated dengue vaccine. The object of the present patent application is a process to obtain a live attenuated dengue vaccine.
The present invention teaches the development of a vaccine against the four types of dengue virus using the attenuated virus strains rDEN1Δ30-1545 (SEQ ID NO:1) and variants thereof; rDEN2/4Δ30(ME)-1495,7163 (SEQ ID NO:2) and variants thereof; rDEN3Δ30/31-7164 (SEQ ID NO:3) and variants thereof; and rDEN4Δ30-7132,7163,8308 (SEQ ID NO:4) and variants thereof. Certain rDEN1Δ30, rDEN2/4Δ30, rDEN3Δ30, and rDEN4Δ30 recombinant attenuated dengue viruses are described in U.S. Pat. No. 7,517,531, U.S. Pat. No. 7,226,602 and U.S. Pat. No. 8,337,860, which are incorporated herein by reference in their entirety.
The vaccine of the present invention, called dengue vaccine 1, 2, 3, 4 (attenuated), is presented in lyophilized form in vials with 10 doses. In the development of this vaccine the following process was established: production of Vero cells and dengue virus of serotypes 1, 2, 3 and 4 to obtain the cell and virus banks; production of viral suspensions with cells and virus from these banks; concentration of these suspensions and preparation of bulks; formulation of monovalent and tetravalent vaccines; filling; lyophilization and sealing of the product.
As may be seen none of the prior art documents discloses or suggests a process for preparing an attenuated tetravalent dengue vaccine that enable dengue vaccine production on a large scale.